Molecular sieve ssz-96

ABSTRACT

A new crystalline molecular sieve designated SSZ-96 is disclosed. SSZ-96 is synthesized using a 1-butyl-1-methyl-octahydroindolium cation as a structure directing agent.

TECHNICAL FIELD

The present disclosure relates to new crystalline molecular sieveSSZ-96, a method for preparing SSZ-96 using a1-butyl-1-methyl-octahydroindolium cation as a structure directing agent(“SDA”) and uses for SSZ-96.

BACKGROUND

Because of their unique sieving characteristics, as well as theircatalytic properties, crystalline molecular sieves and zeolites areespecially useful in applications such as hydrocarbon conversion, gasdrying and separation. Although many different crystalline molecularsieves have been disclosed, there is a continuing need for new molecularsieves with desirable properties for gas separation and drying,hydrocarbon and chemical conversions, and other applications. Newmolecular sieves may contain novel internal pore architectures,providing enhanced selectivities in these processes.

SUMMARY

The present disclosure is directed to a family of crystalline molecularsieves with unique properties, referred to herein as “molecular sieveSSZ-96” or simply “SSZ-96.”

In one aspect, there is provided a molecular sieve having a mole ratioof at least 10 of (1) at least one oxide of at least one tetravalentelement to (2) optionally, one or more oxides selected from the groupconsisting of oxides of trivalent elements, pentavalent elements, andmixtures thereof, and having, in its calcined form, the X-raydiffraction lines of Table 6. It should be noted that the phrase “moleratio of at least 10” includes the case where there is no oxide (2),i.e., the mole ratio of oxide (1) to oxide (2) is infinity. In thatcase, the molecular sieve is comprised of essentially all of the oxideof the one or more tetravalent elements.

In another aspect, there is provided a method of preparing a crystallinemolecular sieve by contacting under crystallization conditions (1) atleast one source of an oxide of at least one tetravalent element; (2)optionally, one or more sources of one or more oxides selected from thegroup consisting of oxides of trivalent elements, pentavalent elements,and mixtures thereof; (3) at least one source of an element selectedfrom Groups 1 and 2 of the Periodic Table; (4) hydroxide ions; and (5) a1-butyl-1-methyl-octahydroindolium cation.

In yet another aspect, there is provided a process for preparing acrystalline molecular sieve having, in its calcined form, the X-raydiffraction lines of Table 6, by: (a) preparing a reaction mixturecontaining (1) at least one source of an oxide of at least onetetravalent element; (2) optionally, one or more sources of one or moreoxides selected from the group consisting of oxides of trivalentelements, pentavalent elements, and mixtures thereof; (3) at least onesource of an element selected from Groups 1 and 2 of the Periodic Table;(4) hydroxide ions; (5) a 1-butyl-1-methyl-octahydroindolium cation, and(6) water; and (b) maintaining the reaction mixture undercrystallization conditions sufficient to form crystals of the molecularsieve.

The present disclosure also provides SSZ-96 molecular sieves having acomposition, as-synthesized and in the anhydrous state, in terms of moleratios, as follows:

Broad Exemplary TO₂/X₂O_(n) ≧10  20 to 100 Q/TO₂ 0.05 to 0.5 0.1 to 0.3M/TO₂ 0.01 to 0.6 0.02 to 0.35wherein: (1) T is selected from the group consisting of tetravalentelements from Groups 4-14 of the Periodic Table, and mixtures thereof;(2) X is selected from the group consisting of trivalent and pentavalentelements from Groups 3-13 of the Periodic Table, and mixtures thereof;(3) stoichiometric variable n equals the valence state of compositionalvariable X (e.g., when X is trivalent, n=3; when X is pentavalent, n=5);(4) Q is a 1-butyl-1-methyl-octahydroindolium cation; and (5) M isselected from the group consisting of elements from Groups 1 and 2 ofthe Periodic Table.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a powder X-ray diffraction (XRD) pattern of the as-synthesizedmolecular sieve prepared in Example 2.

FIG. 2 is a powder XRD pattern of the calcined molecular sieve preparedin Example 3.

DETAILED DESCRIPTION Introduction

The following terms will be used throughout the specification and willhave the following meanings unless otherwise indicated.

The term “active source” means a reagent or precursor material capableof supplying at least one element in a form that can react and which canbe incorporated into the molecular sieve structure. The terms “source”and “active source” can be used interchangeably herein.

The term “Periodic Table” refers to the version of IUPAC Periodic Tableof the Elements dated Jun. 22, 2007, and the numbering scheme for thePeriodic Table Groups is as described in Chem. Eng. News, 63(5), 26-27(1985).

In preparing SSZ-96, a 1-butyl-1-methyl-octahydroindolium cation is usedas a structure directing agent (“SDA”), also known as a crystallizationtemplate. The SDA useful for making SSZ-96 is represented by thefollowing structure (1):

The SDA cation is associated with anions which can be any anion that isnot detrimental to the formation of SSZ-96. Representative anionsinclude elements from Group 17 of the Periodic Table (e.g., fluoride,chloride, bromide and iodide), hydroxide, acetate, sulfate,tetrafluoroborate, carboxylate, and the like.

Reaction Mixture

In general, SSZ-96 is prepared by: (a) preparing a reaction mixturecontaining (1) at least one source of an oxide of at least onetetravalent element; (2) optionally, one or more sources of one or moreoxides selected from the group consisting of oxides of trivalentelements, pentavalent elements, and mixtures thereof; (3) at least onesource of an element selected from Groups 1 and 2 of the Periodic Table;(4) hydroxide ions; (5) a 1-butyl-1-methyl-octahydroindolium cation; and(6) water; and (b) maintaining the reaction mixture undercrystallization conditions sufficient to form crystals of the molecularsieve.

The composition of the reaction mixture from which the molecular sieveis formed, in terms of mole ratios, is identified in Table 1 below,wherein compositional variables T, X, M, and Q and stoichiometricvariable n are as described herein above.

TABLE 1 Components Broad Exemplary TO₂/X₂O_(n) ≧10 20 to 100 M/TO₂ 0.01to 1.0 0.02 to 0.35 Q/TO₂ 0.05 to 0.5 0.1 to 0.3 OH/TO₂  0.1 to 1.0 0.2to 0.6 H₂O/TO₂  10 to 100 20 to 50

In one sub-embodiment, the composition of the reaction mixture fromwhich SSZ-96 is formed, in terms of mole ratios, is identified in Table2 below, wherein compositional variables M and Q are as described hereinabove.

TABLE 2 Components Broad Exemplary SiO₂/Al₂O₃ ≧10  20 to 100 M/SiO₂ 0.01to 1.0 0.02 to 0.35 Q/SiO₂ 0.05 to 0.5 0.1 to 0.3 OH/SiO₂  0.1 to 1.00.2 to 0.6 H₂O/SiO₂  10 to 100 20 to 50

As noted above, for each embodiment described herein, T is selected fromthe group consisting of tetravalent elements from Groups 4-14 of thePeriodic Table. In one sub-embodiment, T is selected from the groupconsisting of silicon (Si), germanium (Ge), titanium (Ti), and mixturesthereof. In another sub-embodiment, T is selected from the groupconsisting of Si, Ge, and mixtures thereof. In one sub-embodiment, T isSi. Sources of elements selected for composition variable T includeoxides, hydroxides, acetates, oxalates, ammonium salts and sulfates ofthe element(s) selected for T. In one sub-embodiment, each source(s) ofthe element(s) selected for composition variable T is an oxide. Where Tis Si, sources useful for Si include fumed silica, precipitatedsilicates, silica hydrogel, silicic acid, colloidal silica, tetra-alkylorthosilicates (e.g., tetraethyl orthosilicate), and silica hydroxides.Sources useful herein for Ge include germanium oxide and germaniumethoxide.

For each embodiment described herein, X is selected from the groupconsisting of elements from Groups 3-13 of the Periodic Table. In onesub-embodiment, X is selected from the group consisting of boron (B),aluminum (Al), gallium (Ga), indium (In), iron (Fe), and mixturesthereof. In another sub-embodiment, X is selected from the groupconsisting of B, Al, Ga, In, and mixtures thereof. In one sub-embodimentX is Al. Sources of elements selected for optional composition variableX include oxides, hydroxides, acetates, oxalates, ammonium salts andsulfates of the element(s) selected for X. Where X is Al, sources usefulfor Al include aluminates, alumina, and aluminum compounds such asAlCl₃, Al₂(SO₄)₃, Al(OH)₃, kaolin clays, and other zeolites. An exampleof the source of aluminum oxide is LZ-210 zeolite (a type of Y zeolite).Boron, gallium, and iron can be added in forms corresponding to theiraluminum and silicon counterparts.

As described herein above, for each embodiment described herein, thereaction mixture can be formed using at least one source of an elementselected from Groups 1 and 2 of the Periodic Table (referred to hereinas M). In one sub-embodiment, the reaction mixture is formed using asource of an element from Group 1 of the Periodic Table. In anothersub-embodiment, the reaction mixture is formed using a source of sodium(Na). Any M-containing compound which is not detrimental to thecrystallization process is suitable. Sources for such Groups 1 and 2elements include oxides, hydroxides, nitrates, sulfates, halides,oxalates, citrates and acetates thereof.

For each embodiment described herein, the molecular sieve reactionmixture can be supplied by more than one source. Also, two or morereaction components can be provided by one source.

The reaction mixture can be prepared either batch wise or continuously.Crystal size, morphology and crystallization time of the molecular sievedescribed herein can vary with the nature of the reaction mixture andthe crystallization conditions.

Crystallization and Post-Synthesis Treatment

In practice, the molecular sieve is prepared by: (a) preparing areaction mixture as described herein above; and (b) maintaining thereaction mixture under crystallization conditions sufficient to formcrystals of the molecular sieve.

The reaction mixture is maintained at an elevated temperature until thecrystals of the molecular sieve are formed. The hydrothermalcrystallization is usually conducted under pressure, and usually in anautoclave so that the reaction mixture is subject to autogenouspressure, at a temperature between 125° C. and 200° C.

The reaction mixture can be subjected to mild stirring or agitationduring the crystallization step. It will be understood by one skilled inthe art that the molecular sieves described herein can containimpurities, such as amorphous materials, unit cells having frameworktopologies which do not coincide with the molecular sieve, and/or otherimpurities (e.g., organic hydrocarbons).

During the hydrothermal crystallization step, the molecular sievecrystals can be allowed to nucleate spontaneously from the reactionmixture. The use of crystals of the molecular sieve as seed material canbe advantageous in decreasing the time necessary for completecrystallization to occur. In addition, seeding can lead to an increasedpurity of the product obtained by promoting the nucleation and/orformation of the molecular sieve over any undesired phases. When used asseeds, seed crystals are added in an amount between 1% and 10% of theweight of the source for compositional variable T used in the reactionmixture.

Once the molecular sieve crystals have formed, the solid product isseparated from the reaction mixture by standard mechanical separationtechniques such as filtration. The crystals are water-washed and thendried to obtain the as-synthesized molecular sieve crystals. The dryingstep can be performed at atmospheric pressure or under vacuum.

The molecular sieve can be used as-synthesized, but typically will bethermally treated (calcined). The term “as-synthesized” refers to themolecular sieve in its form after crystallization, prior to removal ofthe SDA cation. The SDA can be removed by thermal treatment (e.g.,calcination), preferably in an oxidative atmosphere (e.g., air, gas withan oxygen partial pressure of greater than 0 kPa) at a temperaturereadily determinable by one skilled in the art sufficient to remove theSDA from the molecular sieve. The SDA can also be removed by photolysistechniques (e.g., exposing the SDA-containing molecular sieve product tolight or electromagnetic radiation that has a wavelength shorter thanvisible light under conditions sufficient to selectively remove theorganic compound from the molecular sieve) as described in U.S. Pat. No.6,960,327.

The molecular sieve can subsequently be calcined in steam, air or inertgas at temperatures ranging from 200° C. to 800° C. for periods of timeranging from 1 to 48 hours, or more. Usually, it is desirable to removethe extra-framework cation (e.g., Na⁺) by ion exchange and replace itwith hydrogen, ammonium, or any desired metal-ion.

Where the molecular sieve formed is an intermediate molecular sieve, thetarget molecular sieve can be achieved using post-synthesis techniquessuch as heteroatom lattice substitution techniques. The target molecularsieve (e.g., silicate SSZ-96) can also be achieved by removingheteroatoms from the lattice by known techniques such as acid leaching.

The molecular sieve made from the process disclosed herein can be formedinto a wide variety of physical shapes. Generally speaking, themolecular sieve can be in the form of a powder, a granule, or a moldedproduct, such as extrudate having a particle size sufficient to passthrough a 2-mesh (Tyler) screen and be retained on a 400-mesh (Tyler)screen. In cases where the catalyst is molded, such as by extrusion withan organic binder, the molecular sieve can be extruded before drying ordried (or partially dried) and then extruded.

The molecular sieve can be composited with other materials resistant tothe temperatures and other conditions employed in organic conversionprocesses. Such matrix materials include active and inactive materialsand synthetic or naturally occurring zeolites as well as inorganicmaterials such as clays, silica and metal oxides. Examples of suchmaterials and the manner in which they can be used are disclosed in U.S.Pat. Nos. 4,910,006 and 5,316,753.

SSZ-96 is useful in catalysts for a variety of hydrocarbon conversionreactions such as hydrocracking, dewaxing, olefin isomerization,alkylation of aromatic compounds and the like. SSZ-96 is also useful asan adsorbent for separations.

Characterization of the Molecular Sieve

Molecular sieves made by the process disclosed herein have acomposition, as-synthesized and in the anhydrous state, as described inTable 3 (in terms of mole ratios), wherein compositional variables T, X,Q and M and stoichiometric variable n are as described herein above:

TABLE 3 Broad Exemplary TO₂/X₂O_(n) ≧10  20 to 100 Q/TO₂ 0.05 to 0.5 0.1to 0.3 M/TO₂ 0.01 to 0.6 0.02 to 0.35

In one sub-embodiment, the molecular sieves made by the processdisclosed herein have a composition, as-synthesized and in the anhydrousstate, as described in Table 4 (in terms of mole ratios), whereincompositional variables Q and M are as described herein above:

TABLE 4 Broad Exemplary SiO₂/Al₂O₃ ≧10 20 to 100 Q/SiO₂ 0.05 to 0.5 0.1to 0.3 M/SiO₂ 0.01 to 0.6 0.02 to 0.35

Molecular sieves synthesized by the process disclosed herein can becharacterized by their XRD pattern. The powder XRD lines of Table 5 arerepresentative of as-synthesized SSZ-96 made in accordance with themethod described herein. Minor variations in the diffraction pattern canresult from variations in the mole ratios of the framework species ofthe particular sample due to changes in lattice constants. In addition,sufficiently small crystals will affect the shape and intensity ofpeaks, leading to significant peak broadening. Minor variations in thediffraction pattern can also result from variations in the organiccompound used in the preparation. Calcination can also cause minorshifts in the XRD pattern. Notwithstanding these minor perturbations,the basic crystal lattice structure remains unchanged.

TABLE 5 Characteristic Peaks for As-Synthesized SSZ-96 2-Theta^((a))d-spacing (nm) Relative Intensity^((b)) 7.60 1.162 S 8.47 1.043 W 21.000.423 S 22.28 0.399 VS 22.66 0.392 VS 23.64 0.376 W 25.20 0.353 W 26.940.331 W 28.60 0.312 W 29.48 0.303 W 33.20 0.270 W 37.80 0.238 W^((a))±0.20 ^((b))The powder XRD patterns provided are based on arelative intensity scale in which the strongest line in the X-raypattern is assigned a value of 100: W = weak (>0 to ≦20); M = medium(>20 to ≦40); S = strong (>40 to ≦60); VS = very strong (>60 to ≦100).

The X-ray diffraction pattern lines of Table 6 are representative ofcalcined SSZ-96 made in accordance with the method described herein.

TABLE 6 Characteristic Peaks for Calcined SSZ-96 2-Theta^((a)) d-spacing(nm) Relative Intensity^((b)) 7.50 1.178 VS 8.52 1.037 M 14.50 0.610 W20.86 0.425 S 22.26 0.399 VS 22.76 0.390 S 23.60 0.377 W 24.02 0.370 W25.16 0.354 W 26.40 0.337 W 26.94 0.331 W 28.57 0.312 W 29.41 0.303 W^((a))±0.20 ^((b))The powder XRD patterns provided are based on arelative intensity scale in which the strongest line in the X-raypattern is assigned a value of 100: W = weak (>0 to ≦20); M = medium(>20 to ≦40); S = strong (>40 to ≦60); VS = very strong (>60 to ≦100).

The powder X-ray diffraction patterns presented herein were collected bystandard techniques. The radiation was CuK_(α) radiation. The peakheights and the positions, as a function of 2θ where θ is the Braggangle, were read from the relative intensities of the peaks (adjustingfor background), and d, the interplanar spacing corresponding to therecorded lines, can be calculated.

EXAMPLES

The following illustrative examples are intended to be non-limiting.

Example 1 Synthesis of 1-butyl-1-methyl-octahydroindolium cationSynthesis of 1-methyl-octahydroindole

To a solution of 100 g of 1-methylindole in absolute ethanol in a 600 mLautoclave, 5 g of PtO₂ and 10 mL of H₂SO₄ were added. The mixture wassealed and pressurized with hydrogen to 1500 psig. The reaction mixturewas heated at 100° C. overnight while stirring at about 400 rpm. Thereaction mixture was pressurized again to 1500 psig and heated at 100°C. for several more hours. The reaction mixture was cooled and filteredto remove the catalyst. The filtrate was concentrated on a rotaryevaporator to remove ethanol. The residue was neutralized with sodiumhydroxide solution and left to stir at room temperature for about 30minutes. The solution was transferred to a reparatory funnel andextracted with diethyl ether. The ether layer was dried over anhydrousMgSO₄, filtered and concentrated at reduced pressure on a rotaryevaporator to give 93.0 g of the product, 1-methyl-octahydroindole, as ayellow oil. The product was confirmed by NMR.

Synthesis of 1-butyl-1-methyl-octahydroindolium hydroxide

20 g (0.14 mmol) of 1-methyl-octahydroindole was mixed with 53 g (0.29mmol) of 1-iodobutane in 300 mL of methanol. The reaction mixture washeated at reflux for 72 hours. Then, an additional 0.5 mol equivalent of1-iodobutane was added and the reaction mixture was heated for anadditional 12 hours. The reaction mixture was cooled and the solventremoved on a rotary evaporator to give an off-white powder which wasused without further purification. The quaternization afforded 39.4 g(86% yield) of 1-butyl-1-methyl-octahydroindolium iodide. The obtained1-butyl-1-methyl-octahydroindolium iodide (18.15 g) was dissolved in 56g of deionized water. To this solution, 70 g of BIO-RAD AG® 1-X8 ionexchange resin was added and the slurry was gently stirred at roomtemperature overnight. The solution was filtered and the filtrateanalyzed for hydroxide content by titration of a small aliquot withdilute HCl. The exchange afforded 1-butyl-1-methyl-octahydroindoliumhydroxide in 87% yield.

Scheme 1 below depicts the synthesis of the SDA.

Example 2 Synthesis of SSZ-96

A 23 mL Teflon liner was charged with 4.9 g of1-butyl-1-methyl-octahydroindolium hydroxide solution (3 mmol of cationand 3 mmol of hydroxide), 0.75 g of 1N NaOH solution, 0.75 g ofCAB-O-SIL® M-5 fumed silica (Cabot Corporation), 0.25 g of LZ-210zeolite and 2 g of deionized water. The resulting gel mixture wasstirred thoroughly until a homogeneous solution was obtained. The Teflonliner containing the resulting gel mixture was capped off and placed ina stainless steel Parr autoclave. The autoclave was affixed onto a spitrotating at 43 rpm in an oven at 170° C. The gel mixture was heated for6 days after which the reaction was completed to give a settled powderand a clear solution. The reaction mixture was filtered and washedthoroughly with deionized water. The solids were dried in air overnightand then dried in an oven at 120° C. for 2 hours. The obtained solids(0.9 g) were analyzed by powder XRD. The powder XRD pattern of theresulting product is shown in FIG. 1 and indicates that the material wasunique.

Example 3

Calcination of SSZ-96

The as-synthesized product from Example 2 was calcined in air in amuffle furnace from room temperature to 120° C. at a rate of 1°C./minute and held at 120° C. for 2 hours. The temperature was thenramped up to 540° C. at a rate of 1° C./minute and held at 540° C. for 5hours. The temperature was then increased at the same rate (1° C./min)to 595° C. at held at 595° C. for 5 hours. The powder XRD pattern of thecalcined molecular sieve is shown in FIG. 2 and indicates that thematerial remains stable after calcination to remove the organic SDA.

The micropore volume and external surface area of calcined SSZ-96 werethen measured by nitrogen physisorption using the BET method. Themeasured micropore volume was 0.13 cm³/g, the external surface area was59.7 m²/g and the BET surface area was 330.7 m²/g.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the following specification andattached claims are approximations that can vary depending upon thedesired properties sought to be obtained. It is noted that, as used inthis specification and the appended claims, the singular forms “a,”“an,” and “the,” include plural references unless expressly andunequivocally limited to one referent. As used herein, the term“include” and its grammatical variants are intended to be non-limiting,such that recitation of items in a list is not to the exclusion of otherlike items that can be substituted or added to the listed items. As usedherein, the term “comprising” means including elements or steps that areidentified following that term, but any such elements or steps are notexhaustive, and an embodiment can include other elements or steps.

Unless otherwise specified, the recitation of a genus of elements,materials or other components, from which an individual component ormixture of components can be selected, is intended to include allpossible sub-generic combinations of the listed components and mixturesthereof.

The patentable scope is defined by the claims, and can include otherexamples that occur to those skilled in the art. Such other examples areintended to be within the scope of the claims if they have structuralelements that do not differ from the literal language of the claims, orif they include equivalent structural elements with insubstantialdifferences from the literal languages of the claims. To an extent notinconsistent herewith, all citations referred to herein are herebyincorporated by reference.

1. A molecular sieve having a mole ratio of at least 10 of (1) at leastone oxide of at least one tetravalent element to (2) optionally, one ormore oxides selected from the group consisting of trivalent elements,pentavalent elements, and mixtures thereof, and having, in its calcinedform, an X-ray diffraction pattern substantially as shown in thefollowing Table: 2-Theta d-spacing (nm) Relative Intensity  7.50 ± 0.201.178 VS  8.52 ± 0.20 1.037 M 14.50 ± 0.20 0.610 W 20.86 ± 0.20 0.425 S22.26 ± 0.20 0.399 VS 22.76 ± 0.20 0.390 S 23.60 ± 0.20 0.377 W 24.02 ±0.20 0.370 W 25.16 ± 0.20 0.354 W 26.40 ± 0.20 0.337 W 26.94 ± 0.200.331 W 28.57 ± 0.20 0.312 W 29.41 ± 0.20 0.303 W


2. The molecular sieve of claim 1, wherein the molecular sieve has amole ratio of at least 10 of (1) silicon oxide to (2) an oxide selectedfrom boron oxide, aluminum oxide, gallium oxide, indium oxide, andmixtures thereof.
 3. The molecular sieve of claim 1, wherein themolecular sieve has a composition, as-synthesized and in its anhydrousstate, in terms of mole ratios, as follows: TO₂/X₂O_(n) ≧10 Q/TO₂ 0.05to 0.5 M/TO₂ 0.01 to 0.6

wherein: (1) T is selected from the group consisting of tetravalentelements from Groups 4-14 of the Periodic Table, and mixtures thereof;(2) X is selected from the group consisting of trivalent and pentavalentelements from Groups 3-13 of the Periodic Table, and mixtures thereof;(3) n equals the valence state of X; (4) Q is a1-butyl-1-methyl-octahydroindolium cation; and (5) M is selected fromthe group consisting of elements from Groups 1 and 2 of the PeriodicTable.
 4. The molecular sieve of claim 3, wherein T is selected from thegroup consisting of Si, Ge, and mixtures thereof.
 5. The molecular sieveof claim 4, wherein T is Si.
 6. The molecular sieve of claim 3, whereinX is selected from the group consisting of B, Al, Ga, In, Fe, andmixtures thereof.
 7. The molecular sieve of claim 6, wherein X isselected from the group consisting of B, Al, Ga, In, and mixturesthereof.
 8. The molecular sieve of claim 3, wherein T is Si and X is Al.